Empty WSID

[paulmansour]

I know there are certain situations where ⎕WSID is empty where it might surprise us. Does anyone have a list of these places?

I had some code that starts a session from within a session that used to work, but then failed when I moved its location to ⎕SE - though of course there might be other things that have changed. Anyway I had this:

⎕CMD command

which simply started dyalog with a ws, executed some code via ⎕LX and then ⎕OFFed. The code required ⎕WSID to return the location of the ws. This is a synchronous call to CMD. Worked fine until WSID decided to be empty. However if I call it asnync:

⎕CMD command ''

it runs fine. ⎕WSID returns the right thing. Very strange.